Thymosin Alpha-1
Also known as: Tα1, Thymalfasin, Zadaxin
Thymosin Alpha-1 (Zadaxin/Thymalfasin) is approved in several countries for hepatitis and immunodeficiency. It is not FDA-approved for these indications in the US. Research vials are not pharmaceutical grade. For informational purposes only.
Overview
Thymosin Alpha-1 (Tα1) is a 28-amino acid peptide naturally derived from the thymus gland. It plays a central role in regulating immune function — specifically in the maturation and differentiation of T-cells. Unlike most research peptides, Thymosin Alpha-1 has approved clinical use in multiple countries (China, Italy, and others) for hepatitis B, hepatitis C, and as an immune adjuvant in cancer patients undergoing chemotherapy. In the US it is sold as Zadaxin and used as a research compound.
Research Summary
Extensive human clinical research documents Tα1's immune-modulating effects. It increases T-cell counts, enhances NK cell activity, and promotes Th1 cytokine balance. Multiple randomized trials have shown efficacy in treating chronic hepatitis B and C, reducing infection severity in critically ill patients, and improving outcomes in sepsis. More recent research investigates its role in long COVID immune dysregulation. It is considered one of the best-studied peptides in immunology.
Dosing Range
low
900mcg
moderate
1.6mg
high
3.2mg
Units: mg · Frequency: 2–3 times per week subcutaneously
Dosing ranges are aggregated from preclinical research and community protocols. Not medical dosing guidance.
Administration Routes
Reconstitution Notes
Commercially available as lyophilized powder (Zadaxin 1.6 mg/vial). Reconstitute with provided diluent or 1 mL bacteriostatic water. Refrigerate at 2–8°C. Use within 24 hours of reconstitution for best potency.Step-by-step reconstitution guide →
Supplies you'll need
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Reported Side Effects
- Generally very well tolerated
- Mild injection site reactions (most common)
- Transient fatigue in initial doses
- Flu-like symptoms (rare)
Research Papers
4 peer-reviewed sourcesCommunity Experiences
Aggregated from public forums. Anecdotal — not clinical evidence.
Community use patterns focus on immune support during illness or post-COVID recovery. Users note improved energy and fewer sick days during protocols.
View original threadLongevity researchers discuss Tα1 stacks for immune aging. Some users combine with BPC-157 or TB-500 for injury + immune protocols.
View original threadWant to calculate your dose? Use the dosing calculator →